[erlang-questions] jinterface List vs. String

Vlad Dumitrescu <>
Tue Dec 9 11:15:46 CET 2008


Hi,

On Tue, Dec 9, 2008 at 10:54, Robert Raschke <> wrote:
> does anyone have a good idea on how I can distinguish between a list
> and a string in jinterface?

The short answer is that you can't without traversing the list/string.
Since there is no string datatype in Erlang, the two are only
differentiated by their contents.

> Or, in other words, if jinterface has decided to receive an
> OtpErlangString (from a sent list like [1, 2, 3], for example), is
> there an easy way to convert it to an OtpErlangList? I know I can do
> it by hand, but that's ever so slightly icky.

Actually, it is Erlang that decides to encode a list as a STRING_EXTor
as a LIST_EXT, as an optimization.

The way to handle that is by expecting either a list or a string and
convert from each of them to the Java class you're going to use.
Slightly icky, as you say...

Maybe OtpErlangString should have inherited from OtpErlangList?

best regards,
Vlad



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